Enhanced Weathering

What is Enhanced Rock Weathering?

Enhanced rock weathering (ERW) is a nature-based carbon removal technology that permanently locks away CO2. This geological process has happened naturally for millions of years. We simply speed it up.


tonnes of rock


hectares spread


farms enriched


tonnes of CO2 to be removed

Understanding Enhanced Rock Weathering

Discover how nature’s ancient solution meets modern innovation. This brief exploration sheds light on how we accelerate a natural geological process to capture CO2, paving the way for a sustainable future. 

Natural Rock Weathering

As rain falls through the atmosphere, it combines with CO2 to form carbonic acid.

When this dilute acid falls on mountains, forests and grassland, the CO2 interacts with rocks and soil, mineralises and is safely stored in solid carbonate form.

The natural process of weathering already accounts for the removal of 1 billion tonnes of CO2 from the atmosphere every year.

Enhanced Rock Weathering

We accelerate this natural process by spreading crushed silicate rock on agricultural land, increasing the surface area of the rock and therefore increasing its contact with CO2.

Overall, we reduce the timescale from millions of years to mere decades. Once the reaction takes place, the CO2 is permanently locked away for 100,000+ years.

Our climate technology takes a holistic approach, with co-benefits that make our planet a happier, healthier place.

Soil Fertility

Silicate rocks, such as basalt and wollastonite, are mineral-rich. As they weather, they release nutrients such as magnesium, calcium and potassium, improving soil health and reducing the need for fertilisers.

Crop yield

Trials with The University of Newcastle show an increase in crop yield following the application of crushed basalt rock, supporting global food security.

Green Jobs

Our silicate rock reduces costs for rural agricultural communities. Rather than importing machines and talent, we work with local contractors.

Ocean Health

The alkaline bicarbonate ions captured during the enhanced rock weathering process are eventually washed out to sea, where they help deacidify our oceans and are used by marine creatures to build their shells.

Why do we need to remove CO2?

To avoid the worst effects of climate change and slow the planet’s warming, we must now remove the excess CO2 lingering in the atmosphere in addition to reducing our emissions.

Our mission is to spread enough rock by 2025 to remove 1 million tonnes of CO2

We can reverse global warming, and we can do it through permanent carbon removal.


Basalt is a mineral-rich volcanic rock that forms when molten lava cools. It’s highly reactive and weathers over the course of 20 years. It’s also one of the most abundant rocks on Earth, enabling us to scale our operations considerably.

Wollastonite has great carbon capture potential and weathers quickly relative to other silicate rocks. It also has a host of co-benefits for farming communities.

Spreading 1.6 tonnes of wollastonite has the potential to sequester 1 tonne of CO2, whereas basalt takes 4 tonnes spread to sequester 1 tonne of CO2. After spreading wollastonite on agricultural land, it only takes 12 months for 50% of the spread volume to weather. This means that 50% of the wollastonite’s carbon capture potential is achieved only 1 year after the spreading event.

Wollastonite, like basalt, is a silicate rock that contains much-needed nutrients for our soils. These include calcium (Ca2+), magnesium (Mg2+), and potassium (K+). When weathering takes place, these are absorbed into soils which can in turn result in higher crop yield, more pest-resistant plants, and stabilised soil pHs.

Both are safe to use and can significantly improve the health of the soil it’s spread on.

Our basalt is an existing product of aggregate and mining industries, so we aren’t using any additional energy to procure it. By spreading it locally using existing farm machinery, our operations have a 95% carbon efficiency.

Our wollastonite is mined and crushed to order. As wollastonite weathers and captures carbon incredibly quickly, the process has a 90% carbon efficiency.

Any emissions associated with the haulage of both silicate rocks are carefully measured with GPS monitoring and excluded from credits generated.

We believe all carbon removal solutions have a part to play in reversing the climate crisis. However, not all carbon removal technologies offer the same permanence, scalability and co-benefits as ERW.

Projects such as reforestation, while incredibly important for biodiversity, are not permanent. With tree planting, carbon is only locked up for the lifetime of the tree. Wildfires, tree felling and disease also increase the risk of reversal. In comparison, ERW locks carbon dioxide away for 100,000+ years.

Engineered solutions such as direct air capture (DAC) use machinery to capture CO2 directly from the ambient air. This technology offers high durability, but large amounts of energy are required to build the new machinery and then operate the fans. Another key limitation of DAC is that there are very few co-benefits.

ERW offers the best of both worlds as we are accelerating natural solutions with added co-benefits while offering tech-based permanence.

Discover the science

Delve deeper into our climate science and meet the world-leading scientists pioneering our enhanced rock weathering technology.